Azelastine is an active substance having an anti-allergic and asthma-prophylactic effect. The chemical designation is:
4-(p-chlorobenzyl)-2-hexahydro-1-methyl-azepine-4-yl-1-(2H)-phthalazinone (See German Patent No. 21 64 058).
An important mode of administration of azelastine as an anti-allergic agent is orally, in particular in the form of tablets, capsules.
On the other hand, it has not been practical to use azelastine in the form of solutions or suspensions, because azelastine has such a penetrating, bitter taste that patients would refuse to take such azelastine solutions or azelastine suspensions orally. It has also proved impossible to overcome this bitter taste through conversion into a wide variety of salts.